Great photography is undeniable but great photography with a poignant story behind it is even more potent. Such is the case here:

One of the most compelling elements of the continued uprising in Iran has been when each night under the cover of darkness Iranians chant themselves hoarse from the rooftops, balconies, and windows of their homes. This is done to express resolve, hope, frustration, and probably more than anything else, to provide a way that people can be together in spirit and in their cause. As long as the sound of voices echoes through the night, Iran is not yet free. It is the soundtrack of the revolution.

Via Sea of Green.